Account of a Filaria in a Horse's Eye. 289 



frightened, it opens the lid of the left, as well as widens the open- 

 ing of the right eye, which continues disclosed but a short time ; 

 however, this gives an opportunity for inspection for five or six 

 seconds of time together, and the blows must be repeated to keep 

 the eye open when a person wishes to have a longer time for in- 

 spection." 



The similarity of this case to the one now exhibiting, is too 

 obvious to need remark. In all their essential points there is al- 

 most an exact correspondence, viz, the size, color, shape and ap- 

 pearance of the worm ; its incessant motion ; the cloudiness of 

 the aqueous humor, and the partial blindness of the eye. In the 

 case, however, reported by Mr. Hopkinson, the worm appeared 

 to excite more sensation in the eye, and consequently produced a 

 higher degree of inflammation. This no doubt was occasioned 

 by its passing through the iris, and coming in contact with the 

 expansion of the retina and the delicate ciliary processes ; where- 

 as in the present case, the animal is confined exchisively to the 

 anterior chamber of the eye, which is comparatively insensible. 



Origin. — It is a singular fact that some of the first physiolo- 

 gists and helminthologists of the day, attribute the origin of in- 

 testinal and visceral worms to spontaneous gerieration. Such is 

 the opinion of Muller, Bremser, and most of the German physi- 

 cians. The opinion of Linnaeus, that they were terrestrial or 

 aquatic species, taken in with food or drink in the form of ova or 

 germs, is now exploded, for, with the exception perhaps of the 

 FikmUy we do not find the same species of worms wfiich 

 infest animal bodies, out of them. Indeed, Cruvelhier lays it 

 down as an axiom, that worms, like the i7itestinal and vis- 

 ceral, have never been met loith out of the bodies of man and 

 other animals, unless discharged from them; and the con- 

 verse of this he holds to be no less true, viz. that no terrestrial 

 or aquatic ivorms have ever been met with alive, iti the bodies of 

 men and other anim^als, unless they had been very recently intro- 

 duced into them. We might then conclude, with confidence, that 

 worms do not originate from without, but are generated within 

 the body, were it not contended that these animals may have 

 been introduced ab externo, but that in consequence of a change 

 of situation and nutriment, their forms and characteristics are al- 

 tered, as plants and animals are under similar circumstances, and 

 as neuter bees are made prolific, on the loss of the queen bee, by 



